[gandarojin]

Except… WhatsApp definitely gets a copy of your address book: https://www.whatsapp.com/faq/en/general/20971813 “During this entire process, only phone numbers are sent to WhatsApp for lookup, securely, over an encrypted connection.”

[nileshtrivedi]

Whatsapp also gets the metadata about the message: sender, receiver, time and probably location.